JPH0332945Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) This invention relates to an electric expansion valve used in a heat pump circuit, and in particular, the electric expansion valve that can fully open the flow path inside the valve body when the expansion function is not in use. Related to valves.

(Prior art) Conventionally, when trying to make an air conditioner perform both cooling and heating functions, for example, the "Hermetic Refrigerator", written by Mutsuyoshi Kabira, Japan Refrigeration Association, July 1980, was used. A circuit like the one described on page 286 of the 30th issue is used. This circuit is schematically shown in Fig. 6. As shown in the figure, the flow direction of the refrigerant sent out from the compressor 1 is controlled by a four-way switching valve 2, and during cooling, the flow direction of the refrigerant is controlled by the four-way switching valve 2. A cycle is adopted in which the heat is returned to the compressor 1 from the heat exchanger 3 via the cooling expansion valve 4 and the indoor heat exchanger 5.On the other hand, during heating, as shown by the solid line, contrary to the above, the indoor heat exchanger 5 A cycle is adopted in which the air is returned to the compressor 1 via the heating expansion valve 6 and the outdoor heat exchanger 3. The heating expansion valve 6 is used for cooling, and the cooling expansion valve 4 is used for heating.
Since these impede the flow of refrigerant, both expansion valves 4 and 6 are provided with bypass passages 7 and 8, and these bypass passages 7 and 8 are equipped with a checker to allow the refrigerant to pass in only one direction. Valves 9 and 10 are respectively provided.

(Problems to be Solved by the Invention) However, in the above-mentioned device, since it is necessary to connect the bypass passages 7 and 8 having check valves 9 and 10 to each expansion valve 4 and 6, the piping configuration is complicated. This also has the disadvantage of increasing costs.

Therefore, the expansion valve has the following two functions: when the function as an expansion valve is required, it operates as a normal expansion valve, and on the other hand, when the function as an expansion valve is not required, the internal flow path is fully opened and the refrigerant is freely released. The above-mentioned bypass passages 7 and 8
It is conceivable to omit the installation of check valves 9 and 10.

Therefore, as a countermeasure, the stroke of the expansion valve is increased, throttle control is performed when the valve body is close to the valve seat, and the flow path is fully opened when the valve body is moved far away from the valve seat. It is conceivable to adopt this structure, but in this case, the problem arises that the valve as a whole becomes large and expensive. It is also possible to increase the diameter of the valve seat to provide a full opening function.
In this case, a slight variation in the stroke of the valve body causes a large change in the opening area of the valve, resulting in the disadvantage that precise throttle control cannot be performed.

This invention was made to solve the above-mentioned drawbacks of the conventional piping, and its purpose was to make the piping configuration simple and inexpensive by eliminating the need for the bypass passages and check valves that were conventionally used. Moreover, the purpose of the present invention is to provide an electric expansion valve with a full opening function, which is compact in size and can be precisely controlled in the same manner as conventional ones.

(Means for solving the problem) Therefore, in the electric expansion valve with full opening function of this invention, as shown in FIG. 1 corresponding to the embodiment,
Compressor 1, heat source side heat exchanger 3, user side heat exchanger 5
A cooling cycle in which the heat exchanger 3 on the heat source side functions as a condenser and the heat exchanger 5 on the user side functions as an evaporator, and the heat exchanger 3 on the heat source side functions as an evaporator. In a heat pump circuit configured to be able to switch between a heating cycle in which the user-side heat exchanger 5 functions as a condenser, the liquid pipe connecting the heat source-side heat exchanger 3 and the user-side heat exchanger 5 is provided with the above-mentioned It is designed to be interposed together with a pressure reducer 6 for heating cycles. In this device, a first passage 15 connected to the heat source side heat exchanger 3 side and a second passage 16 connected to the usage side heat exchanger 5 side are provided in the valve body 14, and both passages 15, 16 are provided in the valve body 14. are communicated through a first flow path 17 bored in the valve body 14, and the first flow path 1
7 is provided with a first valve seat 20, and the valve body 14 is provided with a first valve seat 20.
A first valve body 18 for opening and closing the first flow path 17 by contacting and separating from the first valve seat 20 is slidably disposed therein, and the first valve body 18 is energized. The first valve seat 20 is urged toward the first valve seat 20 by means 21 . A second passage 24 is provided inside the first valve body 18 to communicate the first passage 15 and the second passage 16.
A valve seat 27 is provided, and a second valve body 25 is slidably provided in the first valve body 18 to open and close the second flow path 24 by contacting and separating from the second valve seat 27. and the second valve body 25 is placed on the valve body 14.
An electric drive mechanism 30 for driving is installed.

Further, in the cooling cycle, the second valve body 25 is moved by the electric drive mechanism 30 with the first flow path 17 closed by the first valve body 18 to perform an expansion action, while in the heating cycle, the second valve body 25 is moved to perform an expansion action. The electric drive mechanism 30 moves the second valve body 25 in the valve opening direction, and the first valve body 18 is separated from the first valve seat 20 by the force of the high-pressure liquid refrigerant acting on the second passage 16. The force of the biasing means 21 is set so as to be able to do so.

(Function) When the electric expansion valve performs an expansion action (during cooling operation in FIG. 1), the first valve body 18 acts as follows.
Since it is urged in the direction of the first valve seat 20 by the urging means 21 and also pressed in the same direction by the high-pressure liquid refrigerant in the first passage 15, the first
As shown in the figure, the valve is in a closed state. Therefore, when the second valve body 25 is driven by the electric drive mechanism 30 to open the valve, the high-pressure liquid refrigerant flows through the first passage 1.
5 to the second passage 16 via the second passage 24, and by adjusting the opening degree of the second passage 24, a predetermined pressure reducing function is achieved. On the other hand, when full opening is required (during heating operation in FIG. 2), the drive mechanism 30 causes the second
The valve body 25 is fully opened. Then, the high-pressure liquid refrigerant in the second passage 16 pushes open the first valve body 18 and flows into the first passage 15, as shown in FIG. At this time, since the flow path area of the first flow path 17 that is opened by opening the first valve body 18 is large, almost no pressure difference occurs before and after this electric expansion valve 13, and the refrigerant flows through this electric expansion valve. 13 can be freely passed through.

(Example) Next, a specific example of the electric expansion valve with full opening function of this invention will be described in detail with reference to the drawings.

1 and 2 show a first embodiment of this invention, in which a plurality of indoor units 12...12 are connected to one outdoor unit 11 as shown in the figure, and indoor heating and cooling is performed. An air conditioner that performs this is shown as an example. Note that since each indoor unit 12...12 has the same structure, only one indoor unit 12 is shown in the figure for convenience. The above outdoor unit 11
is similar to the conventional one described above, and includes a compressor 1, a four-way switching valve 2, an outdoor heat exchanger 3, a heating expansion valve 6, a bypass passage 8, and a check valve 10. The indoor unit 12 also includes an indoor heat exchanger 5.
and an electric expansion valve 13 with a full opening function, which is a feature of this invention.

The electric expansion valve 13 has a valve body 14, which serves as an inlet for high-pressure liquid refrigerant when expanding (during cooling operation in this embodiment) and when fully open (this valve body 14 has a valve body 14). In the embodiment, the first passage 15 serves as an outlet for high-pressure liquid refrigerant during heating operation).
and the second passage 16, which serves as an outlet for the low-pressure liquid refrigerant when expanding (during cooling operation in this embodiment) and an inlet for high-pressure liquid refrigerant when fully opened (during heating operation in this embodiment). It is perforated. As shown in the figure, the passages 15 and 16 extend inward from the first passage 15 to the axial center of the valve body 14, and then extend downward along the axial center of the valve body 14. They communicate with each other by a first flow path 17 extending to. Further, a cylindrical first valve body 18 is slidably disposed at the axial center of the valve body 14, and a valve 19 formed at the tip thereof is connected to a valve 19 provided in the first flow path 17. The first flow path 17 can be opened and closed by contacting and separating from the first valve seat 20. Note that this first valve body 18 is
The valve body 14 is always biased toward the first valve seat 20 by a biasing means disposed within the valve body 14, such as a spring 21 having a relatively weak spring force. Further, the first valve body 18 is formed with a radial through hole 22 that communicates with the inside thereof, and a small axial hole 23 located at the tip thereof. In other words, these through holes 22, the inside of the first valve body 18 and the small holes 23
The second flow path 24 is configured by the above-mentioned first passage 15 and the second passage 1.
6 are connected. A second valve body 25 is slidably disposed inside the first valve body 18, and a valve 26 formed at the tip thereof is connected to the second valve body 25.
The second valve seat 27 provided in the small hole 23 portion of the second flow path 24 is brought into contact with and separated from the second valve seat 27.
The flow path 24 can be opened and closed. A cylindrical case 28 is fixed to the upper part of the valve body 14, and the upper end of the case 29 is sealed with a cap 29.

The second valve body 25 is connected to the electric drive mechanism 3.
0, the drive mechanism 30 will be explained below.
This drive mechanism 30 has a coil 31 attached to the outer periphery of the case 28 and a rotor 32 arranged inside the case 28, and a permanent magnet 33 is fixed to the outer periphery of the rotor. , the rotor 32 can be rotationally driven via the magnet 33 by electrical input such as a pulse to the coil 31. A rotary screw bearing 34 is fixed to the inner circumference of the rotor 32, and this bearing 34 is connected to a fixed screw bearing 3 fixed to the valve body 14.
5 is screwed on. That is, when the rotor 32 rotates, the rotor 32 rotates between the two bearings 34 and 3.
5, and can move up and down as it rotates. On the other hand, the second valve body 25
A base end portion of the rotor 32 passes through the axial center portion of the rotor 32 and is led out to the upper portion thereof, and a fixing ring 36 is attached near the end portion. Further, a spring 37 is interposed between the rotor 32 and the second valve body 25, and the second valve body 25 is urged toward the tip side, that is, toward the second valve seat 27 by the spring 37. Forced. As a result, when the rotor 32 descends, the second valve body 25 is driven downward via the spring 37, while when the rotor 32 ascends, the upper surface of the rotor 32 Valve body 25
By engaging with the fixing ring 36 at this portion, the second valve body 25 is raised. Note that a projection 38 is formed on the lower surface of the cap 29, and this projection 38 is connected to the second valve body 25.
This is to set the limit on the increase in

Next, the operating state of the electric expansion valve will be explained, but first, the operating state during cooling operation will be explained. At this time, the first valve body 18 is urged in the direction of the first valve seat 20 by the spring 21, and is also pressed in the same direction by the high-pressure liquid refrigerant in the first passage 15. Therefore, the valve is in a closed state as shown in Fig. 1. Therefore, when the second valve body 25 is driven by the electric drive mechanism 30 to separate the valve 26 from the second valve seat 27, the high-pressure liquid refrigerant flows from the first passage 15 through the second passage 24. Then, it flows into the second passage 16. Therefore, by adjusting the opening degree between the valve 26 and the second valve seat 27, a predetermined pressure reducing function can be achieved. On the other hand, during heating operation, the second valve body 25 is fully opened by the drive mechanism 30. Then the second passage 1
As shown in FIG.
It will flow into passage 15. At this time, since the spring 21 used has a weak spring force, and the first flow path 17 that is opened when the first valve body 18 opens has a large flow path area, the electric expansion valve Almost no pressure difference occurs before and after the valve 13, the valve 13 is fully open, and the high-pressure liquid refrigerant passes through the expansion valve 13 and is supplied to the heating expansion valve 6. Further, during the cooling operation or heating operation as described above, the operation of a specific indoor unit 12 is stopped by the second valve body 2 by the drive mechanism 30.
5 and closes the second valve body 25 to completely close the expansion valve 13 and stop the passage of the refrigerant.

As described above, when the electric expansion valve is used as an expansion valve, it performs the same function as the expansion valve described above, but when it is not used as an expansion valve, it is fully open and allows free passage of refrigerant. Therefore, when used in a heat pump circuit as shown in FIG. 6, the use of the bypass passage 7 and check valve 9 can be omitted. Therefore, it is possible to simplify the piping configuration and to reduce the cost of the entire device.

In particular, in an air conditioner in which a plurality of indoor units 12...12 are operated by one outdoor unit 11 as in the above embodiment, conventionally, as shown in FIG. In addition to the expansion valve 4, three check valves 39, 40, 4 are provided for switching between cooling and heating and for stopping the unit 12.
1 and one electromagnetic on-off valve 42 and complicated piping, it is now sufficient to use only one electric expansion valve 13 as described above. Therefore, in this case, great effects can be obtained in that the piping work can be greatly simplified, the cost can be significantly reduced, and the reliability of the device can also be improved due to the reduction in the number of parts. Furthermore, the fifth
In the figure, the flow of refrigerant is shown by a broken line during cooling, and by a solid line during heating.

FIGS. 3 and 4 show modified examples of the electric expansion valve. This is a modification of the drive mechanism of the second valve body 25, in which the second valve body 25 is disposed within the first valve body 18, and both 18, 2
5 is biased in the valve opening direction by a spring 43 interposed between the valves 5 and 5. On the other hand, a rod-shaped rotary screw bearing 44 is attached to the rotor 32, and its tip abuts against the base end of the second valve body 25. That is, as the rotor 32 descends, the second valve body 25 is moved by the spring 43.
The valve is closed by being lowered against the force of the rotor 32, and the valve is opened by the force of the spring 43 when the rotor 32 is raised. 45 is a fixed screw bearing, and 46 is a retaining ring for the second valve body 25. FIG. 3 shows the state during cooling operation, and FIG. 4 shows the state during heating operation. The structure of other parts in this embodiment is the same as in the above embodiment, so the same parts are designated by the same reference numerals and their explanations are omitted. However, this electric expansion valve also operates in the same way as in the above embodiment. , therefore it is possible to achieve similar effects.

All of the above examples show examples in which the electric expansion valve is used on the indoor unit side, but the invention is not limited to this, and it is of course possible to use this expansion valve on the outdoor unit side, for example. be. Further, in each of the above embodiments, an example is shown in which a motor is used as the electric drive mechanism 30, but an electromagnetic type may be used.

(Effects of the invention) As mentioned above, the electric expansion valve with full opening function of this invention performs the same function as a conventional expansion valve when used as an expansion valve, but when not used as an expansion valve, it has a high pressure The force of the liquid refrigerant resists the force of the biasing means and the valve is fully opened to allow free passage of refrigerant within the valve, so it is no longer necessary to use a bypass passage or check valve as in the past. This is not necessary, and therefore the piping configuration can be simplified and the cost of the entire device can be reduced. Moreover, the expansion valve itself can be constructed compactly, and precise throttle control can be performed as in the conventional case.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of an embodiment of the electric expansion valve with a full opening function of this invention in a cooling operation state, Fig. 2 is a longitudinal sectional view of the heating operation state, and Fig. 3 is a longitudinal sectional view of a modified example of the electric expansion valve with a full opening function. FIG. 4 is a longitudinal cross-sectional view of the cooling operation state, FIG. 4 is a longitudinal cross-sectional view of the heating operation state, FIG. 5 is a circuit diagram showing a conventional example, and FIG. 6 is a circuit diagram showing another conventional example. 1...Compressor, 3...Outdoor heat exchanger (heat source side heat exchanger), 5...Indoor heat exchanger (user side heat exchanger), 6...Heating expansion valve (pressure reducer), 13... ...Electric expansion valve, 14... Valve body, 15... First passage,
16... second passage, 17... first flow path, 18...
First valve body, 20...First valve seat, 21...Spring, 2
4... Second flow path, 25... Second valve body, 27... Second valve seat, 30... Electric drive mechanism.

Claims (1)

[Scope of utility model registration request] The compressor 1, heat source side heat exchanger 3, and usage side heat exchanger 5 are connected through refrigerant piping, so that the heat source side heat exchanger 3 functions as a condenser and the usage side heat exchanger 5 functions as an evaporator. In a heat pump circuit configured to be able to switch between a cooling cycle and a heating cycle in which the heat source side heat exchanger 3 functions as an evaporator and the usage side heat exchanger 5 functions as a condenser, the heat source side heat exchanger 3 and the user side heat exchanger 5, the electric expansion valve with a full opening function is interposed together with the pressure reducer 6 for the heating cycle, and is connected to the heat source side heat exchanger 3 side. A first passage 15 and a second passage 16 connected to the utilization side heat exchanger 5 are provided in the valve body 14, and both passages 1
5 and 16 are bored in the valve body 14.
The first flow path 17 is provided with a first valve seat 20, and the first flow path 17 is provided in the valve body 14 by contacting and separating from the first valve seat 20. A first valve body 18 for opening and closing is slidably arranged, and the first valve body 18 is biased toward the valve seat 20 by a biasing means 21;
Inside the first valve body 18, the first passage 15 is provided.
A second flow path 24 is provided to communicate with the second passage 16, a second valve seat 27 is provided in the second flow path 24, and a second valve seat 27 is provided in the first valve body 18. 2
A second valve element 25 is slidably arranged to open and close the second flow path 24 by contacting and separating from the valve body 1.
4 is equipped with an electric drive mechanism 30 for driving the second valve body 25, and in the cooling cycle,
With the first valve body 18 closing the first flow path 17, the second valve body 25 is moved by the electric drive mechanism 30 to perform an expansion action. The second valve body 2 in the mechanism 30
5 in the valve opening direction, and the urging means 2 is moved so that the first valve body 18 can be separated from the first valve seat 20 by the force of the high-pressure liquid refrigerant acting on the second passage 16.
An electric expansion valve with a full opening function, characterized by setting a force of 1.